How to Implement l3 protocols in OMNeT++
To implement the Layer 3 (L3) protocols in OMNeT++ encompasses to forming modules that mimicking the actions of network protocols answerable for routing and addressing data packets in a network. L3 protocols embrace commonly in IP (Internet Protocol), OSPF (Open Shortest Path First), and BGP (Border Gateway Protocol). Given below is a procedure to implementing a simple IP protocol, but the similar principles can be put on another L3 protocols.
Step-by-Step Implementations:
Step 1: Set Up OMNeT++ and INET Framework
- Install OMNeT++: Download and install the latest version of OMNeT++ from the OMNeT++
- Install INET Framework: Download and install the INET framework from the INET repository.
Step 2: Define the IP Protocol Module
To create an elementary IP module that handles packet forwarding based on routing tables.
Define the Module in .ned File
Create a .ned file for the IP protocol module.
simple IP
{
parameters:
@display(“i=block/router”);
gates:
input fromUpperLayer;
output toUpperLayer;
input fromLowerLayer;
output toLowerLayer;
}
Implement the Module in C++
Create the corresponding .cc and .h files.
IP.h
#ifndef __IP_H_
#define __IP_H_
#include <omnetpp.h>
#include “inet/networklayer/contract/IRoutingTable.h”
#include “inet/networklayer/contract/IInterfaceTable.h”
#include “inet/networklayer/ipv4/Ipv4Header_m.h”
#include “inet/networklayer/ipv4/Ipv4Route.h”
#include “inet/common/INETDefs.h”
#include <map>
using namespace omnetpp;
using namespace inet;
class IP : public cSimpleModule
{
private:
IRoutingTable *routingTable;
IInterfaceTable *interfaceTable;
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void handleUpperLayerPacket(cPacket *packet);
void handleLowerLayerPacket(cPacket *packet);
void forwardPacket(Ipv4Header *ipHeader, cPacket *packet);
public:
IP();
virtual ~IP();
};
#endif
IP.cc
#include “IP.h”
Define_Module(IP);
IP::IP()
{
}
IP::~IP()
{
}
void IP::initialize()
{
routingTable = getModuleFromPar<IRoutingTable>(par(“routingTableModule”), this);
interfaceTable = getModuleFromPar<IInterfaceTable>(par(“interfaceTableModule”), this);
}
void IP::handleMessage(cMessage *msg)
{
if (msg->arrivedOn(“fromUpperLayer”))
{
handleUpperLayerPacket(check_and_cast<cPacket *>(msg));
}
else if (msg->arrivedOn(“fromLowerLayer”))
{
handleLowerLayerPacket(check_and_cast<cPacket *>(msg));
}
else
{
delete msg;
}
}
void IP::handleUpperLayerPacket(cPacket *packet)
{
Ipv4Header *ipHeader = new Ipv4Header();
ipHeader->setSrcAddress(interfaceTable->getInterface(0)->getIpv4Address());
ipHeader->setDestAddress(packet->getPar(“destAddr”).stringValue());
packet->insertAtFront(ipHeader);
forwardPacket(ipHeader, packet);
}
void IP::handleLowerLayerPacket(cPacket *packet)
{
Ipv4Header *ipHeader = check_and_cast<Ipv4Header *>(packet->removeAtFront<Ipv4Header>());
if (ipHeader->getDestAddress() == interfaceTable->getInterface(0)->getIpv4Address())
{
send(packet, “toUpperLayer”);
}
else
{
forwardPacket(ipHeader, packet);
}
}
void IP::forwardPacket(Ipv4Header *ipHeader, cPacket *packet)
{
Ipv4Route *route = routingTable->findBestMatchingRoute(ipHeader->getDestAddress());
if (route)
{
send(packet, “toLowerLayer”);
}
else
{
delete packet;
}
}
Step 3: Integrate with Simulation Model
Integrate the IP module into a network simulation model.
Network Configuration .ned File
network IPNetwork
{
submodules:
node1: StandardHost {
parameters:
@display(“p=100,100”);
}
node2: StandardHost {
parameters:
@display(“p=300,100”);
}
// Add more nodes as needed
connections:
node1.pppg++ <–> { @display(“m=100,100”); } <–> node2.pppg++;
}
omnetpp.ini Configuration
[General]
network = IPNetwork
*.node*.pppg[*].queue.typename = “DropTailQueue”
*.node*.ipv4.routingTable = “inet.networklayer.routing.manet.Router”
*.node*.networkLayer.networkProtocol.typename = “IPv4NetworkLayer”
*.node*.transportLayer.tcp.typename = “Tcp”
*.node*.transportLayer.udp.typename = “Udp”
*.node*.application[*].typename = “UdpBasicApp”
*.node*.application[*].destAddresses = “node1” // Set destination as needed
*.node*.application[*].destPort = 2000
*.node*.application[*].startTime = uniform(0s, 10s)
*.node*.application[*].sendInterval = uniform(1s, 2s)
*.node*.application[*].packetLength = 512B
*.node*.app[0].typename = “IP”
Step 4: Test and Debug
- Run Simulations: Accomplish simulations to test the activities of the IP module under the different network conditions.
- Analyse Results: Validate the correctness and performance of the implementation.
- Debugging: By using OMNeT++’s debugging tools to troubleshoot any issues.
Step 5: Extend for Other L3 Protocols
To implement other L3 protocols such as OSPF, BGP, etc., follow similar steps:
- Define the protocol’s logic.
- Build corresponding .ned, .cc, and .h files.
- Integrate the protocol with the simulation model.
Overall this paper, we are demonstrated to implement L3 Protocols in OMNeT++. Our team specializes in L3 protocols, including IP (Internet Protocol), OSPF (Open Shortest Path First), and BGP (Border Gateway Protocol). You can rely on our developers for excellent implementation of these L3 protocols in OMNeT++.